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>itf_identity</H1
><DIV
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><A
NAME="AEN9483"
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><H2
>Name</H2
>itf_identity&nbsp;--&nbsp;the identity function</DIV
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><H2
>Synopsis</H2
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>#include &lt;it/math.h&gt;
      </PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>double itf_identity</CODE
>( double x, void *args
        );</CODE
></P
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><H2
>DESCRIPTION</H2
><P
> The <CODE
CLASS="FUNCTION"
>itf_identity</CODE
> function is a very simple it_function which returns the value of the argument <CODE
CLASS="PARAMETER"
>x</CODE
>. It does not have any parameters, therefore, when called directly, <CODE
CLASS="PARAMETER"
>args</CODE
> should be set to NULL. </P
><H2
>RETURN VALUE</H2
><P
>    The same value as 'x'
   </P
><H2
>EXAMPLE</H2
><PRE
CLASS="PROGRAMLISTING"
>&#13;#include &lt;math.h&gt;

...

/* this simply returns 2.0 and assign it to x */
double x = itf_identity(2.0, NULL);

/* create the function x-&gt;x^2 by multiplying two identity functions */
it_function_args(itf_mul) mul_args;

/* multiply the identity function with itself */
mul_args.f = itf_identity;
mul_args.f_args = NULL;
mul_args.g = itf_identity;
mul_args.g_args = NULL;

/* compute the value of the product in 1.0 */
itf_mul(1.0, &#38;mul_args);</PRE
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